1. Field of the Invention
The present invention relates generally to an apparatus and method for monitoring press force severity and press load. Specifically, the present invention relates to a method and apparatus for monitoring dynamic press load without the use of a contact force sensor.
2. Description of the Related Art
Mechanical presses of the type performing stamping and drawing operations employ a conventional construction which includes a frame structure having a crown and a bed and which supports a slide in a manner enabling reciprocating movement toward and away from the bed. These press machines are widely used for a variety of workpiece operations employing a large selection of die sets with the press machine varying considerably in size and available tonnage depending upon its intended use.
A press applies force to a workpiece so that the workpiece (i.e. stock material) acquires the desired geometry corresponding to the die set being utilized. Systems for monitoring press operating reliability assist the press owner in evaluating the impact of certain die/load applications on the reliability of the press being monitored. Conventional monitoring systems include systems which utilize contact load sensors to monitor the peak load being developed within certain components of the press machine during a slide stroke of the press. Known methods of monitoring peak loads utilize an electrical resistance or piezoresistive strain gage or other transducer which is mounted on the press and which voltage change due to resistive change indirectly measures a value of applied load. Monitoring load exerted on load bearing members during a slide stroke of a mechanical press allows press and die applications to be adjusted when monitored peak load values are outside an acceptable range.
What is needed in the art is an apparatus and method to compute the load on a press without utilizing a contacting load sensor.